Method and machine for burnishing the surface of paper



Jul 23, 1946. A R, TRIST 2,404,606

METHOD AND MACHINE FOR BURNISHING THE SURFACE OF PAPER 2 Sheets-Sheet 1 Filed Dec. 30, 1942 July 23, 1946. A. R. TRIST METHOD AND MACHINE FOR BURNISHING THE SURFACE OF PAPER Filed Dec. 30, 1942 I I ,l W- W M- m Patented July 23, 1946 TENT OFEKIE METHOD AND MACHINE FOR BURNISHING THE SURFACE OF PAPER Arthur Ronald Trist, London W. 1, England Application December 30, 1942, Serial No. 470,705 In Great Britain February 21, 1942 8 Claims. 1

This invention relates to improvements in the treatment of the surface of paper to impart to said surface a desired finish in a convenient and economical manner.

The improved method of treatment produces by the simple means referred to, a similar result to that which is obtained by the use of the class of machine known generally as calenders, super calenders or friction glazers and such like, which usually comprise highly polished chilled iron or steel rolls and paper bowls (in which the paper is highly compressed by hydraulic pressure) alternately arranged in a massive housing and requiring both skilled attention and considerable power, that is to say, the treatment imparts a finish to the surface operated on.

The invention contemplates passing the web to be treated between a resilient moving bed and one or more heated elastic blades trailing on and yieldingly co-operating with the web supported by said bed to finish the surface of said web that is contacted by the blade or blades.

The invention further contemplates the use of a suitably supported moving elastic bed, which may be an endless belt or a roller, the working surface in each case being composed of resilient material such as india rubber (natural or artificial) or any other substance capable of co-operating yieldingly with a trailing heated elasticblade or blades to impart the desired finish.

The invention also contemplates the use of one or more elastic blades made of a material which will not mark, that is to say, blacken, or impart other blemish to the web passing thereunder, suchfor example as steel, and so arranged that the edge trailing on the web can be heated in a regular and regulatable manner, for instance, by proximate thermostatically controlled electric heating coils or elements.

A simple machine for finishing paper webs may comprise a roller sheathed in india rubber, water cooled or not, and having one, two or more electrically heated elastic steel blades trailing thereon, the particular finish resulting from the passing of a web of paper between the outer surface of the roller (which travels with the web and supports it) and the blades, seemingly being dependent on the character of the paper Web, the contact width of the blade or blades, the resilience of the sheathing on the roller, the degree of yielding co-operation between the edge or edges of the blade or blades and the web supported by the roller (bearing in mind that during operation the web itself co-operates with the india rubber sheathing and forms a factor in the resilience of the bed at the point or points of operation), the angle of the blades to the surface of the roller, the temperature of the blades and the pressure of the contact edges of the blades on the web supported by the roller.

The actual values of the several factors can be determinedonly by experiment, but in some cases it may be necessary to laminate the steel blades and/or to modify the elasticity thereof by varying the cross section by slots and/or apertures arranged so that the contact edge of such a blade is not interrupted. 7

Whether the webs treated are coated or not, the action of the machine consists in burnishing the surface texture of the web to produce the required finish and gloss.

The invention can be carried into practice by many different mechanical constructions and therefore the arrangement described and shown in the accompanying drawings must be regarded as by way of example only, and in order that the description may be understood reference will be had to the several figures of the drawings and to the letters marked thereon, like letters referring to like or similar parts in the different figures in which:

Figure l is a sectional elevation showing diagrammatically the general arrangement of one form of improved machine for finishing the surface of a web of paper;

Figure 2 is an end View of Figure l partly in section;

Figure 3 is a fragmentary detail of a modified form of blade;

Figure 4 is a cross section of Figure 3 taken on the line 4-4;

Figure 5 is a side elevation of blade;

Figure 6 is an exaggerated schematic View showing the yielding co-operation between an elastic blade and a paper web supported by a resilient bed; and

Figure '7 is a fragmentary detail showingin general form the shape of the edge of a blade.

In the diagrammatic arrangement shown in Figures 1 and 2 the machine comprises'a roller a journalled in side frames b, shown in chain linesin Figure 1, and rotated by a motor 0 so as to have a peripheral velocity of between, say, seven hundred and one thousand feet per minute.

The roller a is of comparatively large diameter, say between forty and fifty inches or so, and it has a thin wall d which is covered or clothed with a layer-e of india rubber (natural or artificial) or other resilient material having such physical a laminated From Figure 1 it will be seen that the web 7' delivered from the supply roll travels in the direction of the arrow it, passes around the roller a and travels in the direction of the arrow Z to the rewind mechanism. v

The required finish is imparted to the external surface of the web 7' by means'of one or more heated elastic blades m which trail'on said surface at parts where the web 7 is supported by the resilient layer e.

In the simplest arrangement the blades m are made of spring steel or of a metal having a similarly'high elastic limit and the composition of V which does not'include nickel, chromium or other ingredient which imparts or are likely to impart any blemish in the form of black marks or smudges, to the surface being treated.

Each blade m is clamped on a'stock n which is pivotally mounted in the arms 0 carried by a shaft p, journalled in the side frames 2), said shaft 20 having mountedthereon a lever q with a dead weight r on the end thereof or a mechanically equivalent spring arrangement.

The ends of the shafts p are threaded and each is provided with a-lock nut o and has a square n so that the stock n can be angularly adjusted by applying keys to the squares n and be clamped in adjusted position by tightening up th lock nuts 0 thus enabling the angle of the blade m on the stock 12 to be set as may be desired.

The heating of the blades m is conveniently effected by thermostatically controlled electrical heaters s which, as shown, are located a short distance away from the under sides of the said blades, dissipation of heat from the exposed blade surface being reduced by means of the sheets if of asbestos cloth or the like.

The excellence and regularity of the finish obtained depends upon the careful correlation of the elasticity of the blade m, the a'ngle of the blade m to the web 7', the pressure per unit of Each particular Web surface requires specialadjustment to obtain a particular finish and the following details will enable skilled Overseers readily to obtain satisfactory results. 1 .If the working face of the blade m is too wide,

.saysixty one thousandths of an inch or so, it;

flattens and irons a paper web without'polishing it, and if the working face of the blade m is too thin, say ten one thousandths of an inch or so,

it scra es the surface and there is a tendency for the fibres to lift a little. V

The temperature of the blade m may be between', say, threehundred' and fifty and five hundred degrees of the Fahrenheit scale, the lower temperatures requiring greater pressure whilst the higher temperatures need less pressure.

The working face of the blade m, is of great importance, it should be highly polished and shaped as shown at m in Figure '7.

' (zero) at the tip of the ripple, passes through a maximum at an intermediate zone on the working face and fades away to a minimum (zero) at the after edge of the depression continuously Ifthecorrect pressure is applied to a blade m at an appropriate angle to suit the elasticity of the and smoothly from zero to zero.

When these conditions have been arranged by adjusting the angle of and selecting the thickness of the blade, adjustment of the temperature usually will produce any required "finish that the paper is capable of taking.

As shown in the drawings the blade m is arranged at forty fivedegrees to a radius but this is by way of example only and may be varied within very wide-limits to suit particular surface requirements. 7 7

Th yielding co-operation between the elastic blades m and the resilient paper covered bed e is of great importance and in some cases that part of the blade'm remote from the working face m may, have slots m cut therein as shown in Figures 3 and 4 or the blade m carrying the Working face m may be reinforced by auxiliary blades to v and so on, to form a laminated structure as shown in Figure 5.

Usually it'willbe found that a single blade m is capable of producing any surface finish obtainable with a given paper web 7' regardless of the sizing used in th manufacture or the coating applied, but the invention is not limited to such single blade and in Figures 1 and 2 two blades are shown although it must be borne in mind that the effect due to the passage under the second blade may be quite diiferent to the effect due to passage under the first blade so that the temperature, angle, elasticity, pressure and/or area of the working face of the second blade may be different to those of the first blade.

Practice has demonstrated that with certain papers there is an advantage in using more than one blade, but such practice also reveals that if too many blades are used the later blades destroy the finish produced by the earlier blades.

I claim:

1. In a method of'burm'shing the surface of paper, the steps of supporting a paper web to be burnished on a resilient bed and pressing a comparatively rigid blade having at its edge a thick of suihcient magnitude to ensure contact between the web and the blade edge over the entire thickness of the latter and with s'uffici'ent force to depress a Zone of said web corresponding substantially to the blade edge into said resilient bed while heating said blade and causing a relative movement of between about 700 and lOOflfeet per minute between the surface of said resilient bed and web on the on hand andsaid blade on the lother hand at substantially right angles to the edge of said blade and in such a way that the body of the blade overhangs the part of the web that is about to pass under the blade edge thereby forming directly adjacent said blade edge in said Jresilie'nt bed a wave'of resilient material, which presses a zoneof said web adjacent said depressed zone of said bed into frictional contact with a surface of said heated blade.

2. In a method of burnishing paper, the steps of supporting a web of paper to be burnished on a resilient moving bed and passing said web and bed at a surface speed of between about 700 and 1000 feet per minute beneath the more than thousandths and less than 60 thousandth of an ing thick edge of a trailing, stationary, comparatively rigid blade in a direction at substantially right angles to said edge and holding said blade at an oblique angle to the moving surface of a sufiicient magnitude to ensure contact between said web and said blade edge over the entire thickness of the latter while heating said blade and pressing the edge thereof with sufiicient force against said web to form an appreciable depression in said resilient bed beneath said edge and to create directly in the rear of said edge a wave of resilient material the advancing front of which L presses the surface of 'the web into frictional contact with the posterior surface of said heated blade.

3. A machine for burnishing paper comprising a resilient movable bed for supporting a paper web to be burnished, means for advancing said bed in one direction at a surface speed of between about 700 and 1000 feet per minute, a resilient stationary blade having at its edge a thickness of more than 10 thousandths and less than 60 thousandths of an inch disposed at right angles to the direction of movement of said bed for working edge of said trailing blade.

trailing cooperationwith its surface thereof at an oblique angle thereto of sufiicient magnitude to ensure contact between a web supported on said bed and the blade edge over the entire thickness of the latter, the relative resiliencies of said blade and bed being so chosen that upon pressure of the edge of said blade against a web supported on said bed the surface of the latter is deformed, means to press the edge of the blade against a web supported on said bed with suflicient force to form an appreciable depression in the surface of said bed beneath said edge and to create directly in the rear of said edge ,a wave of resilient material the advancing front of which presses the surface of the web into frictional contact with the posterior surface of said blade, and means for heating said blade.

7. A machine for burnishing the surface of paper, comprising a resilient roller for supporting on its peripheral surface a web of paper to be burnished, side'frames in which said roller is rotatably journalled, means for rotating said roller at a peripheral surfacespeed of between about 700 and 1000 feet per minute, a stationary, resilient, trailing balde having an edge of more than 10 thousandths and less than thousandths of an inch and arranged parallel to the axis of said roller for cooperation with said peripheral surface, the relative resiliencies of said blade and roller being so chosen that upon pressure of the edge of said blade against a web supported on said roller the surface of the latter is deformed, a stock carrying said blade, said block being ad'- justably supported by said side frames to vary edge a wave of resilient material the advancing front of which presses the surface of the web into frictional contact with the heated posterior surface of said blade.

8. A machine, as claimed in claim '7, including means for water-coolin said resilient roller from the inside thereof.

ARTHUR RONALD TRIST. 

